Kerberos 5 authdata field

[Dave]

I'm currently implementing a very simple server and client program in
C on Linux authenticating using Kerberos 5.  I'm currently using the
sendauth/recvauth functions to perform this authentication and
everything is working well.  However, I'm now trying to utilize the
authdata field in the ticket to send some authorization information to
the server from the client.  I've tried all sorts of different things
but can't seem to get it to work.  Any help on both adding authdata to
the ticket before it gets sent to the sent to the service and
retrieving that information on the service would be appreciated. 
Thanks!